Availability Layer
Also known as: Data Availability Layer, Modular Blockchain Layer, Light Client Data Assurance
A blockchain component responsible for ensuring that transaction data is accessible and verifiable by all nodes.
The availability layer in blockchain architecture guarantees that the data needed to validate blocks is publicly accessible and downloadable by network participants. This layer is crucial in modular blockchains and rollups, where execution and consensus may be separated from data storage. Protocols like Celestia and EigenDA focus on optimizing data availability for Layer 2s. Techniques such as data availability sampling (DAS) allow light clients to verify that block data is complete without downloading everything. A robust availability layer ensures that fraud proofs and zk-proofs can be generated and verified reliably.